MELBOURNE, Australia (AP) — Roger Federer advanced to the Australian Open semifinals for the ninth consecutive year with a 6-4, 6-3, 6-2 victory over Juan Martin del Potro, one of only two men who've beaten him in a Grand Slam final.
After celebrating his 1,000th tour-level match with an emphatic win Tuesday over the 2009 U.S. Open champion, Federer might have to beat the other one — No. 2-ranked Rafael Nadal — to win his fifth Australian title.
The win, sealed with a trademark backhand winner, sets up the prospect of a semifinal against 10-time major winner Rafael Nadal, who was playing No. 7-ranked Tomas Berdych in a night quarterfinal.
Federer and Nadal are on the same half of the draw at a major for the first time since 2005, and No. 1-ranked and defending champion Novak Djokovic is on the other side.
The women's semifinal on the top half of the draw was decided when defending champion Kim Clijsters beat No. 1-ranked Caroline Wozniacki 6-3, 7-6 (4) after third-seeded Victoria Azarenka fended off Agnieszka Radwanska in three sets.
Clijsters has needed continual treatment since Sunday, when she injured her left ankle and had to save four match points in her fourth-round win over Li Na, a rematch of the 2011 final. The 28-year-old Belgian's win on Tuesday means Wozniacki will lose the top ranking, with Azarenka one of three women who could finish at No. 1 in Melbourne.
"Yeah, instead of really focusing on the match you're focusing on trying to get the ankle as good as possible," Clijsters said of her interrupted preparation. "Laying on the couch, every 20 minutes ice, 20 minutes off, 20 minutes ice, 20 minutes off. Leg elevated. Lymphatic drainage, all that stuff."
Federer had no such worries, using his time to work out how to defuse the big forehand of del Potro, who had beaten him two of their previous three matches. He did a stunning job of shutting down the Argentine's big weapons, relying on his exceptional speed to the ball and full range of shots to ensure 11th-seeded Del Potro never had a chance to get settled.
"I'm very happy. It was a great match," said Federer, who has won four of his 16 majors on Rod Laver Arena. "It was a high quality match and Juan Martin is a wonderful player and I know how hard he can hit the ball."
He planned to watch the Nadal-Berdych match on TV, "even though I know both players very well."
"There's no secrets out there, but I'll still enjoy it. I love good tennis."
Tuesday opened with Azarenka beating No. 8 Radwanska 6-7 (0), 6-0, 6-2 to move into the semifinals of a Grand Slam for the second time and maintain a chance of surpassing the Dane at No. 1.
Wozniacki needed to reach the semifinals to retain the top ranking she has held at the end of the last two seasons. Her place in the rankings has attracted some criticism because she's never won a major.
But even after another major setback, Wozniacki remained confident she'll not only reclaim the top ranking but will get her Grand Slam breakthrough.
"You know, I will get it back eventually, so I'm not worried," she said. Critics "talk to me like I'm finishing my career and I only have one year left and time is running out.
"The fact is I still have quite a few good years in front of me."
Clijsters slipped to No. 14 after beating Li Na in the last Australian final, losing in the second round at the French Open and then missing the next two majors due to injuries. But after losing her first four finals in the majors, she's learned how to win them.
She set an example for Wozniacki of how to go about it.
Both players started nervously, with three service breaks until Clijsters held in the fourth game of their quarterfinal. She dictated play from her first hold until she was serving for the match while a break up in the second.
She had the rally on her racket at 30-30, but let her guard down and allowed Wozniacki back into the match. Wozniacki took a chances and got back level, going into the tiebreaker with momentum.
Clijsters had never lost any of her eight previous tiebreakers at Melbourne Park, and she hit a backhand down the line to take a 5-4 lead. She set up double match point with a crosscourt forehand winner and sealed it with a volley.
"It definitely didn't feel like being up a set and 5-2," Clijsters said. "I had to work really hard for it. Caroline is a great fighter.
"I was happy to get through, and not in a three-setter because it's so hot," she said.
Azarenka struggled through a match that contained 15 service breaks, including eight in the first set.
After being comprehensively outplayed in the opening tiebreaker, Azarenka won seven straight games to gain control.
The 22-year-old Belarusian, who makes a distinctive hooting sound as she hits the ball, extended her winning streak this season to 10 matches, including a title at Sydney, where she beat Radwanska in the semifinals. She served six double-faults and had 38 unforced errors, but showed maturing mental resolve but holding her nerve on the big points.
"I'm really happy with my win. I think it was very important to see how I could adjust after not playing really well in the first set," she said. "I completely turned it around.
"Today I really tried to forget about the first set and start from zero and really fight hard. So I think that was a different mental approach a little bit."
Five-time champion Serena Williams is already out of the tournament. Her 17-match winning streak at the Australian Open ended in a 6-2, 6-3 loss to No. 56-ranked Ekaterina Makarova on Monday.
Makarova will face three-time major winner Maria Sharapova, who beat Sabine Lisicki 3-6, 6-2, 6-3. Wimbledon champion Petra Kvitova had a 6-2, 7-6 (2) win over former top-ranked Ana Ivanovic and will next play Sara Errani of Italy.
Novak Djokovic fended off a resurgent Australian veteran Lleyton Hewitt 6-1, 6-3, 4-6, 6-3 to set up a quarterfinal against No. 5 David Ferrer.
Two-time finalist Andy Murray advanced when Mikhail Kukushkin of Kazakhstan retired with a left hip injury while trailing 6-1, 6-1, 1-0. He next plays Kei Nishikori, who beat sixth-seeded Jo-Wilfried Tsonga 2-6, 6-2, 6-1, 3-6, 6-3 to become the first Japanese man to reach the quarterfinals of the Australian Open since the Open era began in 1968.
(This version CORRECTS to 2 men who've beaten Federer in Grand Slam final.)